This invention is directed to a disc brake and more specifically, to a disc brake including brake shoe retaining means which provide for ready access to and removal of the brake shoes.
In order to inspect and remove brake shoes in conventional drum type brake systems, it is usually necessary to remove the wheel and brake drum assembly to gain access to the brake shoes. In disc type brake systems, the brake shoes are usually carried by a housing or caliper secured to the axle inboard of the wheel assembly. In many vehicles there is sufficient open space in the vicinity of the caliper to provide access for the purpose of inspecting, removing and/or possibly relining the brake shoes.
However, in other vehicles the access space is so limited that it is difficult to gain access to the means removably mounting the brake shoes. Even when the mounting means are accessible, many such means are removable in an axial direction and often there is insufficient space to permit complete removal without first moving the wheel or other components of the wheel and axle assembly. This may require rotation of the wheel to move a structural wheel rib or tire tread out of the way or removing an adjacent component.
Accessibility for maintenance purposes is particularly difficult in large off-highway type vehicles. The wheel and axle assemblies of these vehicles include massive components and large tires which leave little open space, are difficult to rotate and may require special equipment if they have to be removed. These difficulties may be even further compounded in off-highway equipment which employ a planetary type drive axle with planetary gear sets mounted axially outboard of the brake.
Replacement or relining of brake shoes is part of the regular maintenance program that must be periodically performed to insure safe and satisfactory operation of a vehicle. Thus it may readily be understood that if the brake shoes and linings are not readily accessible and removable that ordinary maintenance will result in lengthly downtime and increased maintenance costs, both of which increase in accordance with the degree of difficulty encountered in gaining access to, removing and replacing the brake shoes.
Moreover, in view of the difficulties previously encountered, some owners and operators of off-highway equipment are reluctant to attempt to replace or reline brake shoes in the field and thus incur the additional expense of moving the vehicle to a maintenance area.